KR20110074168A - Manufacturing method of a ru powder and ru target material using a waste-ru target - Google Patents

Abstract

PURPOSE: A method for preparing ruthenium powder and a ruthenium target material from a waste ruthenium target is provided to achieve a high-purity and high-density ruthenium target by employing dry processing and plasma rather than wet processing and crushing. CONSTITUTION: A method for preparing ruthenium powder and a ruthenium target material from a waste ruthenium target comprises steps of: removing surface contaminants from a waste ruthenium target(S1), heat-treating the washed waste ruthenium target using plasma to obtain ruthenium powder(S2), pulverizing and classifying the ruthenium powder, and refining the ruthenium powder through heat treatment in the air and hydrogen atmosphere(S3), and hot-rolling the refined ruthenium powder to obtain a ruthenium sintered body(S4).

Description

Manufacturing method of a Ru powder and Ru target material using a waste-Ru target}

The present invention is to prepare a ruthenium (Ru) powder from ruthenium (Ru) waste target by using a plasma, and to prepare a final ruthenium (Ru) target material using the produced ruthenium (Ru) powder, and finally The present invention relates to a ruthenium (Ru) material, which is widely used in a seed layer for forming a magnetic layer according to a large capacity and high density related to a magnetic recording medium or a next generation memory, and specifically, a ruthenium (Ru) powder by regenerating a ruthenium (Ru) waste target. And a method of making a ruthenium (Ru) target material.

The present invention relates to a method of manufacturing ruthenium (Ru) powder of high purity using ruthenium (Ru) waste target, and to manufacturing a high density ruthenium (Ru) target material using the prepared ruthenium (Ru) powder. In detail, compared to the manufacturing process of ruthenium (Ru) powder and target using the wet method, which is widely used recently, ruthenium (Ru) powder is manufactured by using an environmentally-friendly dry method, which has been spotlighted recently, and the high-purity ruthenium ( Ru) powder, and a method for producing a ruthenium (Ru) target material using a pressure sintering method.

In general, a large number of electrode layers or seed layers are formed on wafers or glasses used in connection with next-generation semiconductor memories (RAM, MRAM, FeRAM), heads (MR, TMR), and capacitors. In the method of manufacturing a ruthenium (Ru) sputtering target for forming a ruthenium (Ru) thin film, the ruthenium (Ru) waste target is collected and a ruthenium (Ru) powder is prepared by using a wet method. In the case of manufacturing by wet method, waste targets are collected, and final ruthenium (Ru) powder is prepared by wet dissolution → distillation → concentration → drying → oxidation → heat treatment using strong acid. However, when the wet method is applied, manufacturing time is increased by a complicated process, there is a risk in handling due to the use of strong acid, and high cost is generated due to the considerable amount of waste liquid treatment after use.

Recently, in order to supplement this wet method, the production of ruthenium (Ru) powder using a grinding or dry method has been attempted and commercialized. For example, Japanese Patent Application Laid-Open No. 2009-108400 proposes the preparation of ruthenium (Ru) powder through coarse grinding → hammer milling → leaching → milling → magnetic screening → drying → reduction heat treatment using ruthenium (Ru) waste targets. Doing. The use of the above patent has the advantage of using a large amount of acid or powder production time according to the conventional wet method, but the main process that is applied to the target grinding and refinement of the powder from the beginning of the process (pulverization and fine grinding) In order to solve this problem, an additional process of removing the acid by using acid is introduced.

The present invention is to prepare a high-purity ruthenium (Ru) powder using a ruthenium (Ru) waste target, and to prepare a high-density ruthenium (Ru) target using the prepared ruthenium (Ru) powder, the conventional wet method While introducing an environmentally-friendly dry method, the purpose is to produce a powder by directly introducing a dry method using a plasma instead of a target and a powder grinding method to produce a powder. When the powder is prepared through this, the manufacturing time is shortened compared to the wet method, and the contamination due to excessive grinding is minimized, thereby shortening the process and manufacturing a highly purified powder.

In order to solve this problem, contaminants on the surface of the waste target are removed, ruthenium (Ru) powder is prepared by using plasma, and the final powder is prepared by simple pulverization and classification, and then press sintering is performed. The purpose is to produce a final ruthenium (Ru) target material.

The present invention, by forming a plasma in the ruthenium (Ru) waste target in a vacuum atmosphere or inert atmosphere to produce a ruthenium (Ru) powder and pulverization and classification after the powder prepared by high-purity ruthenium (Ru) through the queue treatment and hydrogen heat treatment To prepare a powder, it is characterized by producing a final ruthenium (Ru) target material through pressure sintering.

As described above, when the wet method known in the art is applied, complicated processes (wet dissolution, concentration, drying and heat treatment) are applied to prepare the powder, which takes a long time of several days or more, and is limited in handling due to strong acid demand. There are a number of disadvantages, including the cost of waste treatment.

In addition, the recently known dry method has advantages such as shortening of manufacturing time and high purity compared with wet method, but it is proposed to solve the problem by applying a wet process in addition to the contamination caused by the target grinding. .

However, the present invention has an advantage in that a wet process can be omitted by introducing a dry method rather than a wet method in preparing the final ruthenium (Ru) powder and preparing the powder using a plasma rather than a grinding method. This shortens the final powder and target L / T and enables the production of high purity and high density ruthenium (Ru) target materials.

The present invention is characterized in that a ruthenium (Ru) waste target is used to prepare a ruthenium (Ru) powder, and to prepare a powder and a target material by using a plasma rather than a conventional wet method and a grinding method. Through this, manufacturing time is significantly shortened compared to the conventional wet method, and ruthenium (Ru) powder may be manufactured by applying an environmentally friendly method by suppressing acid use used for dissolving and removing contaminants.

The method of manufacturing the final ruthenium (Ru) target material is as shown in FIG.

Removing contaminants remaining on the surface of the waste ruthenium (Ru) target using a chemical or physical method (S10);

Preparing a ruthenium (Ru) powder by introducing plasma to the cleaned ruthenium (Ru) waste target (S20);

Preparing a final high purity ruthenium (Ru) powder through a heat treatment by pulverizing and classifying the prepared ruthenium (Ru) powder (S30),

It is characterized by consisting of a step (S40) of producing a high density ruthenium (Ru) sintered body from the final high purity ruthenium (Ru) powder by using a hot pressing method.

Hereinafter, the process steps will be described in detail.

First, the contaminants remaining on the surface of the waste ruthenium (Ru) target are removed.

After use, the surface of ruthenium (Ru) waste targets has a high possibility of surface contamination by handling or surface oxidation due to contamination by Back Depo during sputtering process and long-term atmospheric exposure. In addition, when the powder is manufactured with the contaminants remaining, the contaminants are likely to be mixed in the powder, which is a factor of deterioration of the final target, so it is preferable to remove the contaminants before the powder manufacturing process. Contaminants may be removed by rubbing the surface of the Ruthenium (Ru) melter for a short time by using a chemical method such as shaving the surface, or by removing a certain amount of thickness layer using a physical method such as a mechanical processing method such as a lathe, grinding machine, or MCT. It is possible. In case of removing by using a mechanical processing method, it is desirable to remove the thickness of about 10㎛, because if too thin, the removal of the oxide film, etc. may not be perfect, and if too thick, the final powder yield may be lowered. .

A ruthenium (Ru) powder is produced by forming a plasma on the ruthenium (Ru) waste target from which the contaminants of the surface layer are removed.

Ruthenium (Ru) powder process using a plasma is as follows.

Ruthenium (Ru) waste target from which contaminants of the surface layer are removed is injected onto the mold inside the plasma equipment. Molybdenum (Mo), tungsten (W), copper (Cu), graphite (Graphite), ruthenium (Ru), etc. may be used as the material of the mold, and in order to prevent deterioration of the purity of the final powder, It is important to minimize contamination by the mold, and it is important to select a mold that is easy to remove the contamination even if contamination is caused by the mold. To this end, carbon which is preferably easy to remove is advantageous, and more preferably, it is preferable to use a ruthenium (Ru) mold which does not affect the purity even if it is contaminated.

Plasma is formed by depressurizing the inside of the plasma apparatus into which the material is introduced using a vacuum apparatus, and then inputting a plasma forming gas and applying a constant electric power. It is preferable to use argon (Ar) or N 2 as the gas used for plasma formation, and to use a gas containing a small amount of hydrogen, oxygen, and carbon as a reaction gas to promote vaporization of ruthenium (Ru). It is advantageous to improve the production powder yield and purity. In the case of forming the plasma, in order to ensure the stability of the molten metal, and to suppress rapid temperature rise, the plasma is initially formed at low power to ensure the molten metal stability, and then the power is increased to obtain a powder. When the molten metal is formed by using a plasma, high purity of the molten metal may be expected since the gas component inside the waste target or impurities easily evaporated and easily removed may be removed by vacuum depending on the type of reaction gas. According to the plasma process, ruthenium (Ru) powder having various sizes of 1 to 100 μm is manufactured. When the manufactured ruthenium (Ru) powder is coarse to a level of 100 μm, it is possible to further grind through milling (ball mill, planetary mill, etc.) or jet grinding, thereby making fine ruthenium (Ru) powder. In the case of ruthenium (Ru), the brittleness is strong and easy to grind. The conventional grinding method is applied to a waste target and has a high possibility of contamination due to grinding, whereas in the case of milling applied in the present invention, ruthenium manufactured from a waste target It is possible to minimize the contamination of ruthenium (Ru) powder by grinding because it is applied to the (Ru) powder, the grinding time is short, and much stress is not required for grinding. In order to increase the density of the ruthenium (Ru) sintered body manufactured by the high-temperature pressurization sintering to be performed in a later process, coarse ruthenium (Ru) powder obtained through plasma is preferably controlled to 30 μm or less through grinding. This is because when ruthenium (Ru) powder size becomes more fine, the grinding conditions are severe and the possibility of contamination by grinding is increased.

The prepared powder is subjected to queue treatment and hydrothermal treatment to prepare a final high purity ruthenium (Ru) powder. (S30)

In the case of powder prepared by plasma, carbon is mixed by a mold and a reaction gas, or exposed to the atmosphere for a long time during grinding, and thus highly oxidized. However, when powder is injected into a subsequent sintering process, it is difficult to increase density. When carbon is mixed by the reaction gas or the mold, it is possible to remove it by queue treatment, and the temperature is preferably 800 to 1200 ° C. and heat treatment for 1 to 5 hours. If the temperature is less than 800 ℃ and shorter than 1 hour, the remaining carbon (carbon) is not likely to be sufficiently removed, if the temperature is higher than 1200 ℃ and long time more than 5 hours is likely to agglomerated the powder.

In the case of ruthenium (Ru) powder, which has been queued to remove carbon, ruthenium (Ru) is oxidized to give a blue oxide due to oxidation of ruthenium (Ru), which is subsequently reduced by hydrothermal treatment. Ru) to obtain a powder.

Queued ruthenium (Ru) powder or pulverized ruthenium (Ru) powder is reduced by hydrogen heat treatment to become highly purified ruthenium (Ru) powder. The temperature is 800 ~ 1200 ℃ and heat treatment for 1 ~ 5 hours. desirable. If the temperature is less than 800 ° C and less than 1 hour, ruthenium (Ru) oxide is not sufficiently reduced, because if the temperature is higher than 1200 ° C and long time more than 5 hours, the prepared powder is likely to aggregate.

The high-purity ruthenium (Ru) powder is pressed and sintered to produce a densified ruthenium (Ru) sintered body.

At this time, the applicable hot press sintering can be manufactured using one of HP (Hot Press), HIP (Hot Isostatic Press) and SPS (Spark Plasma Sintering) method, and it is most preferable to manufacture by hot press. desirable. This is because ruthenium (Ru) is easily oxidized at high temperature, and can be reduced when the temperature is higher. When hot press is applied, ruthenium (Ru) partially oxidized in the powder when initially applied at the minimum load. This is because it is possible to reduce the powder and to make some high purity.

The final applied pressure is 10 ~ 80MPa, the sintering temperature is preferably carried out at 1000 ~ 1800 ℃. If the applied pressure is 10 Mpa or less and the sintering temperature is 1000 ° C. or less, a low density sintered body is more likely to be produced. If the temperature is higher than 1800 ° C., a sintered body having coarse grains may be produced to deteriorate the quality of the sputtering target. This is high. In HP using a carbon mold, it is preferable to apply at 80 MPa or less in consideration of the characteristics of the mold.

2 kg of ruthenium (Ru) waste targets used for semiconductors were obtained to prepare ruthenium (Ru) powder. The ruthenium (Ru) waste targets obtained had a purity of 3N5 or more, and the grain size of the target was 20 μm or less. The ruthenium (Ru) waste target was secured by dipping with a cutter, and then deposited on sodium hypochlorite (NaClO) for 5 minutes to remove contaminants on the surface. The cleaned ruthenium (Ru) waste target was made of ruthenium (Ru) powder using a 60kw DC thermal plasma equipment. The manufacturing process is as follows. After depressurization to 10 ^-3 torr using a vacuum pump attached to the plasma equipment, plasma was formed by using N2 and oxygen as a reaction gas to prepare a powder. Indicated.

Table 1

Process item Process condition-Example Tier 1 (Low Power) Stage 2 (high power) Applied Plasma Output (kw) 10 40 Gas for plasma Furtherance N2 N2 + O2 Gas flow rate
(L / min) 20 18 + 2 Gas composition for quenching (flow rate)
(L / min) - 150
(Ar + N2)

 Ruthenium (Ru) powder prepared by plasma was pulverized and classified, and then the final ruthenium (Ru) powder was secured through queuing and hydrogen heat treatment, and ruthenium (Ru) powder, pulverized and classified ruthenium (Ru) was initially prepared. The FESEM image of the powder and the particle size analysis results used in the sintered body are shown in Figure 1 and Figure 2.

[Figure 1]

       Plasma Treated Ruthenium (Ru) Powder Grinding and Classified Ruthenium (Ru) Powder

     [Figure 2]

From Figure 1, the ruthenium (Ru) powder produced through the plasma has a spherical shape and it can be seen that it has a size of less than 100㎛. Further, as a result of further pulverization and classification in order to improve the sinterability, it was possible to prepare fine ruthenium (Ru) powder having a central particle size of 10 μm.

ICP analysis was performed on the powder before and after grinding to determine the contamination by balls during grinding. The analysis showed that the purity of powder before grinding was 99.96%, and the purity of powder after grinding was 99.96%, which was the same as before grinding. . Therefore, it could be seen that there is almost no contamination due to the pulverization of the powder.

The ruthenium (Ru) powder was filled in a carbon mold, and a final ruthenium (Ru) sintered body was manufactured using a hot press (MVHP-350) under an applied pressure of 30 MPa and a sintering condition of 1500x2hr. In order to induce sufficient degassing during the manufacture of the sintered body, the pressure was pressed to the minimum pressure, and the temperature increase rate was also controlled to 5 ° C or less.

For comparison, a commercially available wet ruthenium (Ru) powder was purchased and sintered in the same manner as the dry ruthenium (Ru) sintered body manufacturing method to prepare a sintered body, and then the characteristics were compared. Example 1) In order to evaluate the physical properties of the manufactured sintered compact, a ruthenium (Ru) target, which is commercially available, was purchased, and the characteristics thereof were also compared.

 [Table 2]

Item Example Comparative Example 1 Comparative Example 2 Density (gr / cm3) 12.30 12.31 12.29 Relative density (%) 99 ↑ 99 ↑ 99 ↑ water 99.97 99.97 99.98 Grain (㎛) 13 10 18

Ruthenium (Ru) sintered body prepared by the present invention from Table 2 is the same level of density and purity compared to the sintered body manufactured using a ruthenium (Ru) powder manufactured by a conventional wet method, the ruthenium sold on the market ( Ru) compared with the target was found no difference.

In particular, it can be seen that the grain size of the ruthenium (Ru) sintered body of the present invention is finer than the ruthenium (Ru) target on the market.

1 is a flowchart illustrating a process of manufacturing a ruthenium (Ru) powder and a ruthenium (Ru) target using a ruthenium (Ru) waste target of the present invention.

Claims (8)

In preparing ruthenium (Ru) powder and ruthenium (Ru) target material using ruthenium (Ru) waste target, Removing surface contaminants of ruthenium (Ru) waste targets; Preparing a ruthenium (Ru) powder by subjecting the cleaned ruthenium (Ru) waste target to heat treatment using plasma; Pulverizing and classifying the prepared ruthenium (Ru) powder, Queuing and hydrothermally treating the milled and classified ruthenium (Ru) powder to make the ruthenium (Ru) powder highly purified; Ruthenium (Ru) powder and ruthenium (Ru) target material manufacturing method using the ruthenium (Ru) waste target, characterized in that the step of hot pressing the highly purified ruthenium (Ru) powder to produce a ruthenium (Ru) sintered body . The method of claim 1, wherein the removal of the surface contaminants of the ruthenium (Ru) waste target is a chemical method or surface polishing or a mechanical method of removing contaminants after the ruthenium (Ru) waste target is deposited in a solution such as sodium hypochlorite (NaClO). A ruthenium (Ru) powder and a ruthenium (Ru) target material manufacturing method using a ruthenium (Ru) waste target, characterized by removing contaminants using a physical method such as processing. The method of claim 1, wherein the material of the mold used in the preparation of ruthenium (Ru) powder using the plasma is graphite, copper (Cu), molybdenum (Mo), tungsten (W) or ruthenium (Ru) Ruthenium (Ru) powder and ruthenium (Ru) target material manufacturing method using a ruthenium (Ru) waste target, characterized in that any one selected from. The ruthenium (Ru) powder and ruthenium (Ru) target material manufacturing using ruthenium (Ru) waste targets according to claim 1, wherein the queuing is performed at a temperature of 800 ° C to 1200 ° C and for 1 to 5 hours. Way. The ruthenium (Ru) powder and ruthenium (Ru) target material manufacturing method according to claim 1, wherein the hydrothermal treatment is performed at a temperature of 800 ° C to 1200 ° C and heat treatment for 1 to 5 hours. Way. The method of claim 1, wherein the hot pressing method used in the preparation of the ruthenium (Ru) sintered compact is any one selected from a hot press (HP), a hot isostatic press (HIP), and a spark plasma sintering (SPS) process. Ruthenium (Ru) powder and ruthenium (Ru) target material manufacturing method using a ruthenium (Ru) waste target. The ruthenium (Ru) powder and ruthenium (Ru) target material manufacturing method using a ruthenium (Ru) waste target, characterized in that the pressure applied during the manufacture of the ruthenium (Ru) sintered body is 10 ~ 80MPa. The ruthenium (Ru) powder and ruthenium (Ru) using ruthenium (Ru) waste targets are characterized in that the atmosphere is prepared in a vacuum atmosphere of 10 ^-2 torr or lower. Target material manufacturing method.

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